GEOG 2681: Cartography Spring 2015 Ohio Northern University Roots of the discipline Geo / graphy: “description of the earth.” “a science that deals with the description, distribution, and interaction of the diverse physical, biological, and cultural features of the earth's surface” "The science concerned with the formulation of the laws governing the spatial distribution of certain features on the surface of the earth.“ "...concerned with the locational or spatial variation in both physical and human phenomena at the earth's surface“ “…study the location and distribution of features on the Earth’s surface” [observational science: explain and predict] Geography Oldest of the sciences? 1. 2. 3. 4. 5. Herodotus: father of modern geography • “Historia” mid-fifth century BC Aristotle (384-322 BC): physical geography Eratosthenes (276-196 BC): measures Earth circumference Strabo (64 BC – AD 24): “Geographica” Ptolemy (~AD 150) early cartographer, map maker Geography: oldest of the sciences? At the dawn of humankind, people made crude sketches of geography on cave walls and rocks. These early maps documented and communicated important geographic knowledge our ancestors needed to survive: What is the best way to get from here to there? Where is the water at this time of year? Where is the best place to hunt animals? Our ancestors faced critical choices that determined their survival or demise, and they used information stored in map form to help them make better decisions. SOURCE: “Understanding Our World,” in Essays on Geography and GIS, ESRI 2012, p. 52. • Carto/ graphy: [from Greek Χάρτης, khartes = papyrus (paper) and graphein = to write] is the study and practice of making maps: • Combining science, aesthetics, and technique, cartography builds on the premise that reality can be modeled in ways that communicate spatial information effectively. What is a map? • A map is defined as a representation, usually on a flat surface, of a whole or part of an area. Mapmakers, also known as cartographers, use a variety of tools to make maps • The job of a map is to describe spatial relationships of specific features that the map aims to represent. • There are many different types of maps that attempt to represent specific things. Nature of Cartography Maps: two important functions: storage medium for information 2. picture of the world to help us understand spatial patterns and spatial relationships 1. Analog cartography: procedures of map making Digital cartography: use of technology digital database replacing printed map, cartographic visualizations on diff. media Cartography Today Shortcomings to the use of digital technology: 1. lack of data in readily useable form 2. lack of skilled professionals 3. cartographic development lags behind tech. potential standardization of data software specific formats or data too specialized high costs to convert data quality, exchange, interoperability Map-making shifting from professionals map users need to focus on non-specialists is new for educators Nature of Cartography 1. Maps as forms of communication 2. Characteristics all maps share 3. Effectiveness in thought & commun- ication Maps as forms of communication Forms of knowledge representation: literacy: written language articulacy: spoken language numeracy: symbolizing abstractions, numbers graphicacy: drawing, painting, plans & diagrams describing spatial relationships: map: graphic representation of geog. setting cartography: is the making and study of maps teaching skills of map use, maintaining map collections, data collection, preparing maps, charts, atlases the map: central object that unites all cartographers Basic characteristics of maps 1. 2. All maps are concerned with two elements of reality: location: position in 2-D space (x, y coordinates) attributes: qualities (lang.) or magnitudes (temp.) relationships among: locations with no attributes involved (distance/direction) attributes at one location (temps., precip., soils) location of distribution of one attribute (pop. density) locations of combined attributes (per capita income/educ.) distances, direction, adjacency, insidedness, patterns, interactions = topological relationships Basic characteristics of maps All maps are reductions of reality map is smaller than the region it portrays defined dimensional relationship between map and reality = scale scale sets limit to how much reality is portrayed or included on the map. All maps involve geometric transformations transform round surface to flat map or screen called a map projection choice of projection depends on how map used map referencing system = plane coordinate grids helps calculate distances and directions coordinate systems depend on projection for accuracy. Basic characteristics of maps All maps are abstractions of reality diversity of real world more confusing when reduced show only necessary information data is classified and simplified to make understanding easy All maps use signs or symbols as a representation of reality few words as well as symbols have universal meanings All map symbols use marks lines, dots, colors, patterns... their selection and arrangement? Categories of maps Almost unlimited variety of maps “maps have many functions and many faces, and each of us sees them with different eyes” (Skelton 1972) Problem How to categorize? Categorize from 3 different points of view I. II. III. classed by scale classed by function, or classed by their subject matter. 1. Classed by Scale Ratio of dimension of a map to reality Mapmakers can't draw maps the same size as the area they represent; the maps would be too big. So they draw features smaller than they actually are. What is map scale? The consistent relationship between size on a map and size in real life is called scale. For instance, a map may use one inch to represent what is actually 24,000 inches on earth. Mapmakers express scale as a mathematical ratio, or fraction. The unit on the map is expressed as the number one (numerator). A scale of 1:24,000 would be read as "one to twenty-four thousand." We cannot easily visualize a value such as 24,000 inches, so maps usually not only show the scale ratio but convert the ratio to units of measurement. For example, a 1:24,000 map can also be expressed as 1 inch = 2000 feet, or about four-tenths of a mile. 1. Classed by Scale Ratio Small scale map = large area, very general detail. Around 1:50,000 or less Large scale map = small area, greater detail of dimension of map to reality 1:500,000 or more Medium scale map = everything in between No clear division among the classes 2. Classed by Function classifying maps according to function: no clear distinction among functions of maps Three main categories of maps: General Reference Maps Thematic Maps Charts General Reference Maps Objective? Show locations of various features Large-scale reference maps: Topographic maps photogrammetric methods Larger scale maps: site location/engineering water, roads, coastlines, railroads... great attention to positional accuracy (legal documents) Official map accuracy standards Small-scale general reference maps: states, counties, countries, continents Atlases shows same as large scale, but less detail Thematic Maps Also known as special purpose maps distribution of single attribute or several related if objective is to show location general purpose map thematic maps tend to be smaller scale satellite cloud cover images election results precipitation, temperature population average annual income show geographic distribution over wide area (vs. abs. location) available data > resolution to course regional comparisons vs. site-level decisions Charts Maps especially designed to serve nautical & aeronautical navigators... Maps are to be looked at, charts to be worked on navigators also use general reference maps o maritime equivalent of topographic map bathymetric map Maps are to be looked at, charts to be worked on plot courses, determine positions plot courses, determine positions Two types of aeronautical charts: o visual and instrument navigation Road map is a type of chart land navigation There are few “pure” general ref. or thematic maps o Charts have one specific function 3. Classed by Subject Matter Several important categories of subjects… Cadastral maps: made to accompany the cadastre official list of property owners & land holdings geographic relationship among land parcels cadastres used to assess taxes… Maps referred to as plans: detailed maps showing buildings, boundary lines etc. plans form basis for topographical map series Ordnance Survey of United Kingdom Cartographic representation Principal Communicate environmental information o o job of cartography? mapping costs, accuracy, aesthetics… but mapping effectiveness in thought & communication Treat the making and using of maps equally: Cartographer’s job: enhance map users ability to retrieve information. Map users job: understand the mapping process Series of information transformations: collect select symbolize reading analysis interpret cartographer’s job? ramifications of each stage of process The Scope of Cartography • 1) 2) 3) 4) There are four “processes” in cartography: collecting & selecting data for the map, manipulating & generalizing the data & designing & constructing the map, reading or viewing the map, responding to, or interpreting the map. Have be familiar with other mapping sciences: geodesy, surveying, remote sensing, GIS cognitive sciences (human thought & understanding), and disciplines associated with features being mapped